The advent of multi-component metallic alloys, which exhibit relatively good glass forming ability, has opened opportunities for processing metallic glasses into thick cross section components. The relatively good glass forming ability is important because conventional processing techniques (e.g., casting, extrusion and rolling) may be used to fabricate useful shapes while retaining the excellent engineering properties of an amorphous structure. In particular, the favorable processing characteristics of bulk amorphous alloys are the low cooling rates which can be exercised to yield an amorphous structure and the operating temperature range between the glass transition temperature (Tg) and the crystallization temperature (Tx). Current work is focused on developing a processing strategy that will allow us to fabricate even larger cross section amorphous alloys than are currently achievable by casting methods. The technique involves producing high pressure gas atomized (HPGA) Cu48Ti34Zr10Ni8powders and consolidating them at temperatures above Tg, but below Tx. Thermal analysis of atomized powders by DSC provides details of the influence of powder particle size, which is related to cooling rate during atomization. The results of experiments characterizing the thermal and kinetic behavior of Cu48Ti34Zr10Ni8powders indicate that short processing times are required to retain the amorphous structure during consolidation in the temperature regime between Tg and Tx.
Available at: http://works.bepress.com/thomas_lograsso/163/